test-drb October 2020

test-drb@ccmp.vtda.org

136 participants
117 discussions

by decguy＠songdog.eskimo.com

Looking to complete a period-correct DEC workstation? Missing the right mouse? Have I got a deal for you! Digital 3-button mouse part number 30-44445-01 rev. C02. PS/2 connector, ball mechanism (not one of those fancy new things with the red light on the bottom). Free for actual cost of shipping. This wasn't what I was looking for in storage either.

3 years, 6 months

DEC RTM book

by dstalk＠execulink.com

I've searched for this but couldn't find it... Does anyone know if the DEC book "RTM: Register Transfer Modules" published in 1973 is available online? It's an 8.5 x 11 book with red cover and has 50 pages. I think it came with their RTM kit. Don

3 years, 6 months

non-shunting jumpers?

by brian＠quarterbyte.com

Hi all, Oddball question here: has anyone ever seen a way to cap off or protect standard 0.1" pin header jumpers? Maybe there exist jumper plugs that *don't *conduct across the two pins? I'm looking at a piece of hardware that has some jumper pins on top of the PC board and I'd like to protect against anything accidentally making contact. I have seen surface mount 0.05 pitch pin headers come from their manufacturer with protective caps, but I haven't been able to find anything to apply to 0.1" pin headers that I could by aftermarket. Any ideas would be appreciated! thanks brian

3 years, 6 months

The weird stuff I keep finding: 19 bit core memory?

by cz＠alembic.crystel.com

Now I'm starting to look through boxes to see if I have another 11/24 CPU. I seem to recall picking a second one up somewhere, I also want to see if I still have the driver board for the second Plessy core memory. Might be around, might have been pitched. So far I did find a box of DZ11's. Not sure why I have a dozen of them, they might have been from the USPS haul in days of yore. Anyone need a couple of DZ11's? The real weird one is a quad board H216. I thought it was a Unibus core memory board, but it's 8k*19 bits, which means it came from one place: An MA10 memory box. The only one I may have been exposed to was AI (the original KA10). So question: Did AI use MA10 memory boxes? Did any of that stuff survive? Anyplace else it might have come from? Weird stuff. Got a lot of it.... CZ

3 years, 6 months

The weird stuff I keep finding: 19 bit core memory?

by jnc＠mercury.lcs.mit.edu

> (Whether that's all done on the companion driver boards, and the H21x > card would just bring the wiring of the two banks out to the edge > connector in parallel, letting the driver board do what it wants, I > don't know - you'd have to look at the MM11-L engineering drawings/TM.) > The other possibility is that the PDP-10 memory used these boards in > pairs. It's not either! First, I looked at the MM11-L TM, and it talks about how the H214 has "mats" (2D arrays of cores), 1 mat per bit; the H214 has 16 mats. So definitely no effectively 36+ bit wide variant. So, pairs? Well, I looked to see what PDP-10 memory TM's were extant, and there's one for the MF10 (A-MN-MF10-0-MAN-1); and glancing in it, it _does_ use the H216 - with "19 mats" to produce "19-bit word memory banks"! (Exactly how, I didn't have time to stop and read. It's got to be pairs, but at the bank level, not board.) So our guess as to which generation of PDP-10 memories it was used in might have been wrong... Noel

3 years, 6 months

FYI sunhelp.org down

by macro＠linux-mips.org

Hi, I posted to <rescue at sunhelp.org> and saw my message got stuck in the mail queue. Upon a further inspection I saw that the domain has expired along with `mrbill.net' where the nameservers used to reside and both have been taken by someone else, taking the name service down for `sunhelp.org'. I can still reach Bill Bradford's personal page when I connect to the server by its IPv4 address at: <http://184.94.207.190/>. I do hope nothing bad has really happened to Bill in these difficult times. Anybody knows? Maciej

3 years, 6 months

The weird stuff I keep finding: 19 bit core memory?

by jnc＠mercury.lcs.mit.edu

> From: Chris Zach > My guess is the H215 has two more core fields on it I uploaded a (crappy - sigh) image of an H215 I have to here: https://gunkies.org/wiki/File:H215-core-memory-board.jpg and it's clearly not symmetrical, but does have a slightly bugger blank space than yours. It has a label that says "18x8K" (so 16 bits plus byte parity - for DATOB bus write operations to one byte at a time), which sounds orrect. > Odd they could fit up to 20 bits, maybe an early ECC (16b+4 ECC?) No, this way pre-dates ECC memory (the cost of the extra bits - more cores to string in - was probably more than it was worth), and probably before ECC disks too (I think the first DEC ECC disk was the RP04). > I'll bet that it could work in the 11/05 if one of those boards ever > blow out. That's my guess too; _but_ there might be some jumpering/etc issues to adjust the word width. I.e. the PDP-11 parity H215 is 18 bits wide, which is right for 16-bit words, whereas PDP-10 parity memory would be 36+1 parity bit = 37 bits wide. So there might be 2 banks on one of those cards, and the PDP-11 memory treats them as separate banks, whereas on a -10 they'd be ganged together in parallel. (Whether that's all done on the companion driver boards, and the H21x card would just bring the wiring of the two banks out to the edge connector in parallel, letting the driver board do what it wants, I don't know - you'd have to look at the MM11-L engineering drawings/TM.) The other possibility is that the PDP-10 memory used these boards in pairs. We do have the MA10 Maint Manual, but in a quick look it looks like it doesn't use these boards. So maybe a later -10 memory system? Noel

3 years, 6 months

non-shunting jumpers?

by jfoust＠threedee.com

At 01:30 PM 10/22/2020, you wrote: >I have seen surface mount 0.05 pitch >pin headers come from their manufacturer with protective caps, but I >haven't been able to find anything to apply to 0.1" pin headers that I >could by aftermarket. I'd use two jumpers. Hang one off one pin, hang the other off the other. If you wanted to get fancy, superglue them in the middle. - John

3 years, 6 months

The weird stuff I keep finding: 19 bit core memory?

by rshepprd＠gmail.com

There?s a piece of core on eBay https://www.ebay.com/itm/DEC-Digital-H214-Digital-Equipment-Core-Memory-Lit… which claims to be H214. The interesting thing is the label says 8K x 16 but the silkscreen says 8K x 19. Sent from Mail for Windows 10

3 years, 6 months

The weird stuff I keep finding: 19 bit core memory?

by jnc＠mercury.lcs.mit.edu

> From: Richard Sheppard > There's a piece of core on eBay .. which claims to be H214. The interesting > thing is the label says 8K x 16 but the silkscreen says 8K x 19. DEC did that a lot; used one silkscreen (and etch) for two different modules, with differing componet sets to produce two different boards (e.g the MSV11-D and -E: http://gunkies.org/wiki/MSV11-D_MOS_memory M8044 and M8045 respectively; the boards all say 'M8045' in the etch, you have to look at the handles). The H214 is the 16-bit wide version of this board, used in the MM11-L UNIBUS memory: https://gunkies.org/wiki/MM11-L_core_memory The parity MM11-LP uses the H215 (an 18-bit wide version), and a G109 instead of the G110 (again, same etch, some components left off for the G110. There's also an H213, used in the MM11-K: https://gunkies.org/wiki/MM11-K_core_memory which is an 8KB version; the H213 looks identical to the H214 at first glance, but if you look closely the core mats are only half as dense. Noel

3 years, 6 months

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test-drb October 2020